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Thursday, October 6, 2011

Control Harmony

Harmonized Controls make a huge difference at 30' AGL and 65MPH

I started flying in the fall of 1976. It was an American Aerolight Cirrus 5B "hang glider". It had a 5 to 1 glide ratio and was considered a great machine in its day. For the record, it was light in pitch and heavy in roll. That lead me to later fly Cessna's, Pipers, etc. which is discussed in greater detail in the Gyro Journal. Some like the Corby Starlet was very nicely harmonized and was a blast to fly.

All of the experiences of flying different types, categories, etc. gave me an appreciation for an aircraft that was properly harmonized for pressures, travel and feel. When flying an aircraft of any type, if roll is light and pitch is heavy, you will have a tendency to over control on roll and be slow on your pitch inputs. Conversely, if roll is heavy and pitch is light you will have a tendency to over control in pitch and be slow on your roll inputs. The magic however is to "match" or harmonize the pressures and responses of the control stick systems. Like most things, this is easier to talk about than to do in real world flying. This is further complicated by the airspeed of the aircraft you are flying. An example of this is the Japanese Zero of WWII. American pilots flying P-38's were trained to keep the Zero's engaged at speeds above 250 MPH. Why? Because at this speed the Japanese pilots needed to use two hands on the control stick to dog fight due to heavy control stick pressures; in spite of being beautifully harmonized at "all air speeds" pressures in both axis's increased at the same time; requiring more force (read muscles here) with the increased speed. This "two handed" approach made the aircraft difficult to maneuver precisely at higher speed and more importantly made it even harder to reach the gun triggers that were mounted on the left side of the cockpit. At 250+ MPH it was hard to fly and shoot and chew gum at the same time. Below 250MPH, it was a different story....often favoring the Zero which then became easier to fly with one hand and shoot with the other. IE: Speeds at which the aircraft offered manageable forces with its harmonized controls.

For the HoneyBee G2, our goal has been to create a harmonized pitch/roll condition where pressures gradually increase in both axis's with increased airspeeds; sounds like the Zero doesn't it? A benefit of this is the aircraft is solid at speed and more maneuverable at slower speeds, like the Zero. Bringing this back to our G2 world, when you are flying an open frame the pressures will be different (lighter) than when that same frame is fitted with a full enclosure and it now goes 40 - 50% faster. At these speeds, what used to work has to be re-tuned in moments and leverages to restore "that lovin' feeling" again. What is the solution? It is "tune ability"! For those that have seen the G2's, you have seen it in our control stick output arms; it is in our interim arms and it is now included with the Moving Mast "trombone slide" control linkages. This feature will continue to be part of our strategy as we seek to provide you all with an aircraft that meets your specific needs today and at the specific time you need it....no matter how fast you end up going.